They've been mistaken for UFOs or dismissed as hallucinations. Now geologists have collected a near-definitive list of a rare but fascinating phenomenon — earthquake lights.

Certain types of earthquakes in certain areas can set off blazes of light seconds — sometimes days — ahead of the actual quake. These can manifest themselves as floating balls of light, bluish columns shooting up out of the earth and even reverse lightning, reaching up into the sky from the ground.

A study out Thursday in the journal Seismological Research Letters shows such quakes are tied to a specific type of temblor in areas where certain geological formations occur.

"'When a powerful seismic wave runs through the ground and hits a layer of such rocks, it compresses the rocks with great pressure and speed, creating conditions under which large amounts of positive and negative electrical charges are generated,' he said. These charges can travel together, reaching what's called a plasma state, which can burst out and shoot up into the air."

If the formation hypothesis is correct, then do you think it would be possible to recreate this phenomenon on a smaller scale? The Caltech Shockwave Lab comes to mind.

"'When a powerful seismic wave runs through the ground and hits a layer of such rocks, it compresses the rocks with great pressure and speed, creating conditions under which large amounts of positive and negative electrical charges are generated,' he said. These charges can travel together, reaching what's called a plasma state, which can burst out and shoot up into the air."

If the formation hypothesis is correct, then do you think it would be possible to recreate this phenomenon on a smaller scale? The Caltech Shockwave Lab comes to mind.

Don't know about earthquake lights but it was done with ball lightning...

Well, maybe. No one had been able to produce anything in the lab that exhibits all of the characteristics associated with ball lightning. Most notably, everything seen in the lab is either extremely short lived or requires some form of external energy.

With respect to earthquake lights, I am reminded of this comment from a seismologist.

When scientists are skeptical about the existence of reported phenomena, they often try to cover up under a layer of humor. Such an attempt by one seismologist led him to remark that "the chapter on earthquake lights is the darkest in seismology."

No longer does this subject lurk in the shadows of scientific skepticism. Among the more illuminating observations that have brought this topic out into the scientific light of day are those acquired by a Japanese dentist. He managed to photograph earthquake lights occurring during a ten-year earthquake swarm starting in 1965

Their claim was BL would result when lightning from a cloud strikes the ground causing some silica contained in the soil to be vaporized. Somehow the oxygen would split from the silicon dioxide, resulting in pure silicon vapor. While cooling this silicon would condense into an aerosol and then recombine with the oxygen, causing it to glow. This process has not yet been reproduced in the laboratory, as far as I know.

The recent analysis by the Chinese team shows the spectrum of a glowing sphere that contains emission lines from silicon, iron, and calcium. These are elements expected to be found in soil. Although this mechanism may describe one type of BL, it cannot account for all types of BL. Observations of BL appear within buildings after passing through closed doors and closed glass windows, and within metal aircraft, having both entered and exited without causing damage. Since silicon nanoparticle aerosol cannot pass through solid barriers, the theory does not explain all BL formations.

Since our Forum Discussion Guidelines do not allow speculations that go beyond or counter to generally-accepted science, and since there is no “generally-accepted science” that describes Ball Lightning, I cannot answer your question here. I would, however, consider a Personal Message exchange on the subject.

Pssst...Are you talking about the small blackhole hypothesis thingy?
And could you refer me to the reports where BL has been said to pass through solid barriers? (I am drawing a blank on google...)

Since our Forum Discussion Guidelines do not allow “speculations that go beyond or counter to generally-accepted science”, and since there is no “generally-accepted science” that describes Ball Lightning, I cannot answer your question here.

If I were to simple rearrange these in the order of what I believe is the most likely to least likely scientific explanation, then that would be in violation of the PF rule regarding personal theories. I invite anyone here to use our Personal Message system if she would like to search with me for a better understanding of BL.

If I were to simple rearrange these in the order of what I believe is the most likely to least likely scientific explanation, then that would be in violation of the PF rule regarding personal theories.

Oh, I don't think so. Some of those are quite reasonable scientific theories.

Of particular interest to physics students should be the discovery of unexpected electrical activity generated by a humble box of kitchen flour.
"The results were presented at the American Physical Society’s March Meeting in Denver on Thursday by Rutgers University biomedical engineer Troy Shinbrot. His lab has created a miniature model of earthquake-like jamming and cracking, and has found huge voltage jumps that result from the shifting of granular material used to mimic the earth.

He used tanks filled with different types of grains, from kitchen flour to glass beads, and moved them relative to one another in a quick start-and-stop motion to create cracks. A non-contact voltage probe focused on measuring a certain crack. The voltages differed from material to material, but the overall pattern remained the same. When the grains split open, they measured a positive voltage spike, and when the split closed, a negative spike.

Sometimes the voltage ­changes were as high as hundreds of volts — but as of now, the researchers cannot explain why."